Using existing methods, particle sensors for measuring the contents of aerosols are tested in a test chamber, where the chamber is filled with a known particle concentration. The readings from the particle sensor can then be compared with the known particle concentration in the chamber to evaluate the accuracy of the particle sensor. This evaluation typically requires exposure of the external surfaces of the particle sensor to the test aerosol, and the particle sensor, therefore, becomes contaminated. Sensor testing can typically only be conducted in the laboratory because of the complexity of the test setup. Additionally, testing typically is unreliable at low particle concentration levels; and the establishment of a stable, low particle concentration is very difficult to achieve. Nevertheless, testing at low concentration levels may be necessary to test sensor limits of detection, which can be important for detecting harmful biological organisms or other toxic items, where detection at very low concentrations levels may be important.